Clinical and Histopathologic Spectrum of Toxic Erythema of Chemotherapy: A Series of 56 Cases From a Single Institution.

Introduction: Although many individual cases and small series of toxic erythema of chemotherapy (TEC) have been described, the full spectrum of findings is not well understood.

Objective: To provide a comprehensive review of the clinical and histopathologic features of TEC with an emphasis on novel histopathologic findings.

Methods: We searched our electronic medical record for "toxic erythema of chemotherapy" or "neutrophilic eccrine hidradenitis." Fifty-six cases meeting clinical and histopathologic criteria were identified. The electronic medical record and accompanying hematoxylin and eosin-stained slides were retrospectively reviewed.

Results: The clinical findings were heterogeneous but included classic presentations such as intertriginous eruptions (34%) and acral erythema (25%). The most common histopathologic features were apoptotic keratinocytes (95%), basal vacuolar change (91%), and epithelial dysmaturation (79%). Eccrine squamous syringometaplasia was seen in over half of the cases (33/56; 59%), whereas neutrophilic eccrine hidradenitis was uncommon (16%). Interestingly, many cases showed prominent interstitial histiocytes (55%). Other novel findings included irregular orthohyperkeratosis (23%), irregular epidermal hyperplasia (14%), and acantholysis (9%).

Limitations: As a retrospective study, it is subject to information bias.

Conclusion: This is the largest reported series of TEC. In addition to confirming previously reported features, we identify novel histopathologic findings to add to the spectrum of TEC.